The objective of this project is to investigate the potential of saliva as a biological medium that can be non-invasively obtained for the screening of elevated lead levels in humans. The goals of the feasibility study are threefold: (a) to select a convenient method of specimen collection; (b) to adapt an analytical method to measure the concentrations of lead expected in the specimen; and (c) to determine the correlation of lead in blood and saliva from simultaneously collected specimens. Saliva will be collected either as an ultrafiltrate collected in the mouth with an osmotic device, or by means of a special swab, or as whole saliva either expelled directly or collected with a pipette. The concentration of lead in saliva will be measured by graphite furnace atomic absorption spectroscopy (AAS) with palladium as a modifier. Lead concentrations in saliva are normally lower than concentrations in blood. Therefore, the sensitivity of the AAS method will be enhanced 50 to 100-fold to make the reliable measurement of lead in saliva possible. Finally, matched samples of blood and saliva will be collected from individuals exposed to a different extent to lead and the concentrations will be correlated. These investigations will provide the groundwork for a comprehensive study, performed in Phase II, that results in the recommendation of threshold levels for lead in saliva as specimen.